Apparatus and process for drying.



W. M. GRSVENOR.

APPARATUS AND PROCESS FOR DRYING.

APPLICATION FILED AP11.9|I9D9.

Patented May 11, 1915.

STATES PATENT oEEIcE.

APPARATUS AND PROCESS DBYINQ.

Specication of Letters Patent.

Patented May 11, 1915.

Application led April 9, 190B. Serial N o. 485,981.

tures because they areliable to fusion in the i early stages of drying and to decomposition 1f the process is prolonged. `Hitherto these products have commonly been dried in rooms having no systematic clrculation of air but in which the surrounding air was used so that it was subject td climatic variations and sudden changes in weather conditions, and in which no effective effort was made to eliminate the large` quantities of bacteria p usually found in the air which was used as a drying medium. In the absence of proper means to control both the temperature and humidity the sudden rises of temperature, particularly if accompanied by high humidity, are likely to cause the glue to melt and run down through the nets upon which it is supported, so that it is thus lost or contaminated.

Various objects of my invention are to provide a method and system for drying glue and similar materials, in which the dr ing medium is under thorough control, 1n which the drying takes place in a substantially closed chamber, so or that the bacteria and dust from the outer air are eliminated, and to provide a method and system in which any dust and bacteria which may be initially in the air or drying medium may be satisfactorily removed therefrom; in which the material to be dried is first` subjected to the drying medium under conditions under which it is most effective without melting the glue or other perishable material, and then subjecting the glue or material to the drying medium under different conditions under which it is still more effective for drying. To do this I provide a system in which the material while ro ressing on its way fromone point of t e actory-to another is subjected to the action of a series of regressively varied drying conditions, eac adapted to dry the material as rapidly as its properties, on reaching that particular zone yof create or determine these conditions and the location of these zones that their relative positions shall be independent of weather variations. d

Another feature of my invention is t'o provide a system in which the material is moved from zone to zone and arranged so that it may be readily accessible at all times when in either of its critical stages or points of drying, that isat the initial drying or point of insertion of the material in the system and at the point or zone of final drying or completion of the treatment.

A further feature of my vinvention is to first subject the glue or other perishable material to the action of relatively cool air movingrapidly across its surface in a more or `less upward direction in order to produce what is termed the Skinning of the under surface thereof to create a sort of receptacle or container of drier material to prevent the glue falling through the nets on which it is supported.

A further feature of my invention is to so arrange the apparatus that the various steps of the `process are carried out most eiliciently and economically and so that the drying medium is caused to pass entirely over and between the glue or other material in a most e'ective and economical manner.

Further objects, features and advantages of my improvements will more clearly appear from the detailed description given beow taken in connection with the accompanying apparatus embodying one form of my invention and arranged to carry out one j form of my improved process.

In the drawing, Figure 1 is a sectional plan view of my improved apparatus showing two substantially duplicate alleys. Fig.

2 1s a sectional vertical view of one of the alleys shown in Fig. 1.

Referring to the drawing, `1 represents the frame of two,alleys A and B. Each alley is provided at its endswith automatically closed doors 2, 2 and 3, 3, and is'horizontally and longitudinally divided into two pgrts by a partitlon 1', the size of each part ing substantially the same. In the upper part of the alley7 1s placed a heatingmeans 4 consisting of steam pipa.- suita ly arranged and provided with an mlet pipe 5. A short distance back of the heaters 4 I provide a coolin or refri erating means 6 providedwith in et pipes and outlet pipes 8 for the purpose of properly cooling and drying the drying medium. This refrigerating means is made of anysuitable type, one form, however, which I consider very eiicient is` that known as the Vento type. Just back of and adjacent to the refrigerating means 6 I locate a fan or propelling means9 placed within a transverse plate 10 and driven by a motor 11, the motor 11 being held in position by cross-pieces 12. At each end of each alley the division piece 1 is cut away to form an opening between the upper and lower portions o the alley as at 4 and 5. The upper portion of each alley is provided with doors 13 which may be opened in case it is desired to enter the upper part of the alley for any purpose. Upon the bottom 14 of each alley are arranged tracks 15 which are inclined from the forward end 16 of the apparatus toward the rear end 17, thereof, so that a space 18 is provided between the floor 14 and the tracks 15 or any bodies which may be placed upon the tracks, which space gradually increases from the front end 16 to the rear end 17.

The glue is arranged within the lower part of each alley upon nets 19, which nets are located upon trucks 2O adapted to be rolled upon the tracks 15. In order to prevent the air or drying medium from passing around the outside edges of the glue nets 19 I provide resilient bailies 21 on the sides and top of the lower half of each alley, these,baiiies being made of leather or some suitable material and secured to the walls of the alley in any suitable manner. At each end of the lower half of each alley the same `is made larger by being cut away as at 22,

so that more space is provided at these points for the air or drying medium to pass, first, downward through the opening 4 around the glue nets, and, secondly, upward through the opening 5 away from the glue nets. In order to properly collect and conduct away the condensed water and particles carried with it I provide a drip pan 23 located underneath the refrigerating means 6, which pan is provided with an outlet pipe 24 for conducting away the condensate.

The operation of my improved process and apparatus is as follows: The glue containing from 60 to 95 per cent. of water after being chilled to from 40 to 60 degrees Fahrenheit and cut into small slabs is spread as closely as possible on the glue nets. The nets are then stacked on trucks as shown to such a height as will insure their contact with the upper baiiles 21, reasonable care being taken to preserve their lateral alinement, and preferably a false top net is used to cover the top of the pile. With the outlet doors 3 closed the inlet doors are thrown open and one or more trucks of fresh glue are pushed in or allowed to run gently forward on the tracks 15. The heating and refrigerating means 4 and 6 being in operation the motor 11 is started up so that the fan 9 will drive the air through the cycle indicated by the arrows, the air being irst pro pelled by the fan against the refrigerating means where moisture therein is condensed and carried away by the drip pan 23. From the refrigerating means 6 the air is forced through the heating means 4 whereby it is warmed to the proper temperature. Upon leaving the heating means the air is forced downward through the opening 4 and then longitudinally through the various glue nets 19, and consequently comes into thorough contact with the surfaces of the glue thereupon. Since the bailes 21 prevent the dryin medium from escaping about the top and sides of the glue nets a greater current of air is forced underneath the glue nets and between the trucks and floor 14 to come into contact with the glue nets located at the middle of the alley and at the rear end 17 of the alley. At the rear end the drying medium is allowed to pass upwardly through the openings -5 whence it is drawn or sucked by thefan 9 and again forced against the refrigerating means 6.

When the pile of glue nets at the front end of the alley have become suliiciently o1' completely dried, which may be determined upon examination by opening door 3, these glue nets are removed and the remaining nets are allowed to run along the tracks 15 to a new position or zone. After the door 3 is closed the door 2 may be opened and a new pile of nets may be inserted at that end. This opening of the doors does not allow of any appreciable amount of outside air getting into the apparatus since when one door is opened at one end the doors at the other end will be closed, to prevent any draft which will draw the outside air into the apparatus. The doors may be provided with weather strips in order to Vmake the same tight. After passing through the glue nets 19 the air is sucked or drawn at a relatively reduced pressure by means of the fan 9 up through the opening 5. It is then put under a relatively high pressure (its maximum pressure) and at this pressure is propelled or forced directly against the refrigerating means 6 which is so arranged with fiat and angular surfaces that the medium is greatly baffled. The medium being propelled against the staggered flat surfaces of the cooling means 6 the moisture therein which has been collected from the glue is condensed therefrom and any particles of dust or bacteria which may have gotten into the air are effectively removed at the same time. This removal of bacteria and dust is greatly facilitated by the lacing of the fan directly back of the re rigerating means 6, since thereby the air or heating medium is impelled at a great velocity against the bafiiing surfaces of the refrigerating means so that the dust and bacteria are -forced into contact` with the moist bafliing surfaces and are collected thereby. The greatly cooled, dried and purified air or drying medium after being heated by the heating means 4 passes downwardly through the opening 4 whence it is forced through the lue racks at a slightly reduced pressure. gl`he drying medium, therefore, enters the glue racks at a relatively high temperature and pressure and with a relatively low humidity. As the medium passes toward the rear of the alley through the glue racks it becomes gradually cooled and the pressure thereof gradually decreased and its humidity gradually increased due to the absorption of moisture from the glue. Thus each of the various piles of fglueracks situated throughout the length o the alley occupies a zone of different characteristics. and conditions, so that the glue racks which have just been placed within the alley are first subjected to a drying medium of relatively low temperature and pressure and ofrelatively high humidity. At this stage substantially all of the drying energy is directed against the under side of the glue so that the under surface of the glue is quickly dried so that a bottom Skinning thereof is effected. As the glue nets are step by step run forward toward the front end of the alley they are subjected to a drying medium of greater temperature and greater pressure and having less humidity. When the glue racks have reached the front end 16 of the alley and the glue is in the final stage of' drying it is subjectedv to the drying medium at a greater pressure and at its highest temperature and when its humidity is at its lowest. The gradually increasing space 18 beneath the pile `of glue racks 19 causes a very decided upward current of air to take place at the rear end of the alley as shown by the arrows. This upward current of air causes the bottom of the glue slabs to be dried more quickly and, therefore, to provide a sort off dried ooatin on the underneath side of the glue, whic preventsthe same from fusing and `running through the glue nets. Yet atthe'same time the upper surface of the glue-remains wet and perfectly open forevaporation. The strong upward pull of the fan 9 .also increases the `upward movement ofthe drying medium to make the above action more effective. By thus providing different zones of drying medium having different characteristics I am able to finally subject the glue to a drying medium at higher temperatures and pressures than could otherwise be practicably obtained. This is because I first subject the glue to a drying medium of relatively low pressure and temperature whereby it is revented from melting in its first stages o drying. After it becomes partially dry I find that the temperature and pressure can. be safely raised and this is most eco- `nomically and eihciently carried out by pro-vv end and removed from the other the glue at' the front end, which has been completely dried, may be removed `and racks of fresh glue may be inserted at the rear end without in any way stopping or hindering the process of drying, The material at its critical stages or zones, that is, at the point of initial drying or Skinning and at the point of final drying or completion is at all times free of access.

By subjecting the glue to relatively cool air moving rapidly across its surface in a more or less upward direction which insures the earliest possible drying of the under surface thereby creating a sort of receptacle or container of drier material, which prevents the glue from passing through the nets or other supported means, the market value of the glue is greatly increased since one of the indications of a good uality glue is the slightness of the marks left by the supporting means which gradually indents the lower surface to a greater depth the longer said surface remains undried. It will also be apparent that by placing the fan directly back of the refrigerating means I more eii'ectively cool and dry the drying medium andr also effectively remove all dust and bacteria from the drying medium to purify the same. This is important since if the drying medium contains many bacteria the glue becomes contaminated and will be of very inferior quality. It will further be seen that the air purifying means with the arrangement shown,'points out a particularly simple and eicient system for purifying air or gas for any purpose. Passage of the air through the glue highly humidifies it, after which it, is comp and propelled directly against the staggered baffling members of the Vento condenser, so that the bacteria, etc., adhereto the moist surfaces which are washed by the condensate and real purification effected- By providing the baics 21 on the sides and top of the alley the drying medium is caused to flow through the ends and over the glue in a most effective man Althou I have described my improvements wit great detail I do not desire to be limited to such details, but

Having fully and clearly described my invention what I claim as new and desire to secure by Letters Patent is :y

1. In an improved process for drying glue and similar materials, coolin and purifying the drying medium, heating the cooled and purified drying medium, subjecting the material to the heated drying medium at a relatively low pressure and then subjecting the material to the drying medium at a materially increased pressure.

2. In an improved process for drying glue and similar materials susceptible of being injured or contaminated by suspended matter in the drying medium, said process consisting in circulating the drying medium in a cycle closed upon itself and in a suitable inclosure, introducing the material into4 the drying medium at one point in said cycle, purifying the drying medium by refrigeration at one point in said cycle where any air admitted to the cycle will be purified before it engages the material, and removing the material at still another point in said cycle where the pressure is greater than atmosphere to prevent the ingress of unpurified air.

3. In an improved process of drying glue and similar materials susceptible of being injured or contaminated by suspended matter in the drying medium, said process consisting in circulating the drying material ina cycle closed upon itself and in a suitable inclosure, purifying it by refrigeration, compression and impingement against moist surfaces at substantially its highest pressure at one point in said cycle and where any air admitted to the cycle will be purified, introducing the material into the drying medium, and removing the material at a point in the cycle where the pressure is greater than atmospheric, to prevent the ingress of unpurified air.

4. In an improved process for drying glue and similar materials liable to melt, first subjecting the glue or similar material to a current of drying medium passing in an upward direction through the glue or similar material to initially dry the under surface of the glue and then further subjecting the glue or similar material to drying operations.

5. In an improved process for drying glue and similar materials liable tojmelt, subjecting the glue ory similar material to a current of a relatively cool and humid drying medium at a pressure less than atmospheric, passing in an upward direction against the lower surface of the glue or similar material to form a skin on said lower surface, and then subjecting the glue to substantially horizontal currents of drying medium at relatively increased temperatures, and decreased humidity and at materially relatively increased pressures.

6. The improved process for drying glue or similar materials liable to melt which consists in first subjecting the glue or similar material to upward currents of a relatively cool and humid drying medium at a pressure less than atmospheric, to form a container of drier material on the under surface of the glue or similar material, and then subjecting the glue or similar material to currents of drying medium at greater temperatures and pressures and having lesser humidity and velocities.

7. The improved process for drying glue or similar materials which consists in purifying and heating the drying medium and projecting the glue or similar material to the drying medium at relatively low temperatures and then at relatively higher temperatures.

8. In an improved process for drying glue and similar materials subject to fusion when subjected to moderate temperatures in a moist state, submitting the"\moist material to the drying medium at elevated temperatures and reduced pressures, so that increased evaporation shall restrain overheating the material and when partly dried then subjecting the material to the drying medium at materially increased temperatures and pressures, and purifying the drying medium by refrigeration and impingement prior to said last mentioned treatment of the material.

9. The improvement in processes for drying glue and similar materials, which consists 'n first exposing the fresh material to a dryi g medium when relatively cool and humid, propelling the drying medium in a substantially closed circuit in which the medium is heated, cooled by evaporation, propelled and purified, and moving the material progressively through the medium between the points of heating and propulsion in a direction counter to that in which the drying medium is moving.

10. The combination of a substantially closed chamber composed of two passages having substantially the same available cross-section, means therein for heating the drying medium, means for propelling the drying medium in a substantially closed circuit in the' chamber, and means between the propelling means and the heating means for refrigerating the drying medium and purifying the same, said refrigerating means embracing a plurality of cooled pipes in staggered relation.

11. In a drying apparatus, a closed chamber arranged to form a continuous substantially closed circuit for the drying medium, means whereby the material to be dried may be inserted at one part of the circuit and withdrawn at another part of the circuit, means for heating the drying medium, means Vfor refrigerating the drying medium, and means for propelling the drying medium directly against the refrigerating means so that the drying medium will impinge upon the same at its maximum velocity, said refrigerating means consisting of a plurality of sets of cooled pipes in staggered relation.

12. In drying apparatus, a chamber in which the material to be dried may be placed, means whereby the material may be inserted at one end of the chamber and removed from the other end thereof, means Vfor mechanically propelling the drying medium through said chamber in a substantially longitudinal direction over the material in the larger part of the chamber, means for causing the drying medium to travel in an upward direction through the material and at an increased velocity at the end of the chamber at which the material is inserted, and means for removing moisture from the drying medium.

13. The combination of a chamber composed of two passages having substantially the same equivalent section in one of which material to be dried may be placed, means whereby the material may be inserted at one end of the chamber and removed from the other end thereof, means for propellingy a drying medium through said chamber be ow atmospheric pressure in a direction counter to the movement of thefmaterial, connecting means to the other passage, refrigerating means and heating means in this passage, and means for causing the drying medium above atmospheric pressure to How against the refrigerating means at a Velocity greater than that of the medium when it first passes about the material to be dried.

14. In drying apparatus, a substantially closed chamber suitably partitioned in which the material to be dried may be placed, means whereby the material may be inserted at one end of the chamber and removed from the other end thereof, means for pro elling the dryin medium in a substantially closed cycle trough said chamber, and means arranged to provide a s ace beneath the material increasin in size rom the removing end of the cham er to the receiving end thereof to cause the drying medium to be properly distributed about the material.

15. In glue drying apparatus, a structure having a passage for the glue racks anda passage connected with the iirst mentioned passage at both of its ends, a heater and refrigerat-ing means in said second mentioned passage and means directly back of the refrigerating means to propel the drying medium directly against it, said refrigerating means consisting of a plurality of pipes arranged transversely of the passage.

16. In dryin apparatus, a structure having a passage or the material to be dried, and a passage above'and over said first mentioned passage connecting with the rst mentioned passage at both of its ends, and propelling means in said second mentioned passage arranged to suck or draw the drying medium upwardly through the material at one end of said first mentioned passage where the material is introduced.

17. In a drying apparatus, the combination of a passage for the material to be dried, a passage above and over the said first mentioned passage and connected with said first mentioned passage at both of its ends, heating and condensing apparatus in ,said upper second mentioned passage and propelling means arranged to suck the drying medium upwardly through the material to be dried at one end of said first mentioned passage.

18. In drying apparatus, a structure having a passage for the material to be dried and a passage connectin with the first mentioned passage at both o its ends, means for preventin the drying medium from passing aroun the material except at the bottom thereof and means for propelling the drying medium through said Ipassages.

n testimony whereof, have signed my name to this specification, in the presence of two subscribing witnesses.

WILLIAM M. GROSVENOR.

Witnesses GoRHAM Cnosr, EDWIN Snom.

1t is hereby certified that in Letters Pater' No. l,l38,75l, granted May l1, 1915, upon the application of VVlliam M. Grosvenor` of Grantwood, New Jersey, for an improvement in Apparatus and Processes for Drying, an error appears in the printed specification requiring correction as follows: Page 4, line 129` and page 5, line 54, for the Word pipes read members; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Ofiiee.

Signed and sealed this 6th day of July, A. D., 1915.

[SEAL] R. F. WHITEHEAD,

Acting Commissioner of Patents. 

